Description of problem:
This bug is similar with bug 889995 but for different devices. In this bug I listed the non-default devices like usb device,virtio-serial, virtio balloon, qxl vga type, etc. 
Create separate bugs because tracking all devices in one bug maybe a little muddle,huge and hard to set the priority. 
Of course any suggestions or method to track multiple devices issue are welcomed. 

Version-Release number of selected component (if applicable):
RHEL6.4 host:
kernel2.6.32-348.el6.x86_64
qemu-kvm-0.12.1.2-2.346.el6.x86_64

RHEL6.0-z host:
kernel-2.6.32-71.40.1.el6.x86_64
qemu-kvm-0.12.1.2-2.113.el6_0.8.x86_64

How reproducible:
Always


Steps to Reproduce:
1. Boot a guest on rhel6.0 host and attach as more devices as possible that 6.0 supported.
# /usr/libexec/qemu-kvm -S -enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name rhel6.1-64 -uuid 69f4aa4b-a575-348e-934b-0c27f138c735  -monitor stdio -rtc base=utc -no-shutdown -boot order=nc,menu=on -drive file=/home/disk.qcow2,if=none,id=drive-ide0-0-0,format=qcow2,cache=none -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0  -drive file=/home/boot.iso,id=drive-cdrom,format=raw,if=none,werror=stop,rerror=stop,media=cdrom -device ide-drive,drive=drive-cdrom,id=cdrom -netdev tap,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:8a:36:ae,bus=pci.0,addr=0x3 -netdev tap,id=hostnet1 -device e1000,netdev=hostnet1,id=net1,mac=52:54:00:8a:36:20,bus=pci.0,addr=0x4 -netdev tap,id=hostnet2 -device virtio-net-pci,netdev=hostnet2,id=net2,mac=52:54:00:8a:36:20,bus=pci.0,addr=0x5 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device AC97,id=sound0,bus=pci.0,addr=0x6 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x8 -chardev socket,id=channel0,host=127.0.0.1,port=12345,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=channel0,id=channel0,name=com.redhat.rhevm.vdsm -k en-us -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device usb-tablet,id=input0  -device usb-kbd,id=kbd -device usb-mouse,id=mouse  -drive file=/home/disk-2.qcow2,if=none,id=drive-virtio0,format=qcow2,cache=none,rerror=stop,werror=stop -device virtio-blk-pci,bus=pci.0,addr=0xa,drive=drive-virtio0,id=virtio0  -drive file=/home/floppy.img,if=none,id=drive-fdc0-0-0,readonly=on,format=raw -global isa-fdc.driveA=drive-fdc0-0-0 -vnc :10 -vga std -watchdog i6300esb -watchdog-action pause 

2. On 6.0 host:
(qemu)info qtree

3. Boot guest on rhel6.4 host with the same command line as step 1 but append "-M rhel6.0.0".

4. (qemu)info qtree

5. Compare the output on step 2 and step 4. 
  
Actual results:
Lot's of properties are different, some properties showing up on 6.4 host but not on 6.0 host.
Some property values are changed on 6.4 host.
Here only highlight some of them, for detail please check attachment. 
(Blue front means "properties exists on 6.4 but not on 6.0;
 Red front means "property value changed on rhel6.4 host")

Highlight:
(1) "dev-prop: indirect_desc = on" for virtio devices on rhel6.4 host with -M rhel6.0.0, but on rhel6.0 host, it is "dev-prop: indirect_desc = off"

(2) with -vga qxl frontend, lot's of properties changed or new properties showing up on rhel6.4 host. That make migration between 6.0<->6.4 failed.

(3) Lots of properties value changed for virtio-net-pci driver and some new properties showing up on 6.4 host, for detail please check the attachment.



Expected results:


Additional info: